Systems and methods for improved 3d printing

ABSTRACT

A system includes a first system configured and arranged to combine at least two different input materials; a controller coupled with the first system and configured to independently control a feed rate for each of the different input materials into the first system to generate a processed material that varies in composition along its length; and a second system configured and arranged to add syncing features to the processed material. The syncing features are useable by a material deposition system to synchronize the variation in composition of the processed material during additive manufacturing of an object using the processed material. The controller can configured to create data usable by the material deposition system to sync the processed material with locations of the object during additive manufacturing. Further, the second system can include a material shaping system, and the syncing features can include shapes added to the processed material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Patent Application No. 61/955,214, entitled SYSTEMS AND METHODS FORIMPROVED 3D PRINTING, filed Mar. 19, 2014, and this application isrelated to U.S. patent application Ser. No. 14/663,393, entitled SYSTEMSAND METHODS FOR IMPROVED 3D PRINTING, filed on Mar. 19, 2015. Thedisclosures of the above applications are incorporated herein byreference in their entirety.

BACKGROUND

This specification relates to three dimensional (3D) printing oradditive manufacturing, such as fused deposition modeling (FDM).

FDM using extruded polymer filament has evolved rapidly and is usefulfor creating reasonably accurate three dimensional objects quickly.Current FDM printing is typically accomplished by forcing a solidplastic feedstock through a heated nozzle with smaller diameter than theoriginal feedstock. The filament is liquefied before or as it passesthrough the constriction in the nozzle, and the feed pressure causesmaterial to be extruded with a cross section approximately equal to thenozzle exit. Other 3D printing techniques referred to in thisapplication include selective laser sintering (SLS), stereolithography(SLA), direct metal laser sintering (DMLS) and material jettingprocesses such as ObJet.

SUMMARY

This specification relates to 3D printing or additive manufacturing,such as FDM. In general, one or more aspects of the subject matterdescribed in this specification can be embodied in one or more systemsthat include a first system configured and arranged to combine at leasttwo different input materials; a controller coupled with the firstsystem and configured to independently control a feed rate for each ofthe different input materials into the first system to generate aprocessed material that varies in composition along its length; and asecond system configured and arranged to add syncing features to theprocessed material. The syncing features are useable by a materialdeposition system to synchronize the variation in composition of theprocessed material during additive manufacturing of an object using theprocessed material.

Implementations according to this aspect may include one or more of thefollowing features. The different input materials can include at leastthree filaments having at least three respective different colors, thecontroller can be capable of continuously varying an amount of each ofthe at least three different colored filaments, and the first system caninclude: an input material feed system for the at least three differentcolored filaments; and a mixing chamber having adjacent restrictionorifices where the filaments enter the mixing chamber, and the mixingchamber having an exit orifice with a width that is smaller than themixing chamber. In addition, the syncing features can include markersplaced into or on the processed material at controlled locations.

In the systems of this aspect, the controller can be configured tocreate data usable by the material deposition system to sync theprocessed material with volumetric or surface locations of the objectduring the additive manufacturing. The material deposition system can bea different fused deposition modeling (FDM) system, and the controllercan be configured to create the data in a data file usable by thedifferent FDM system.

The second system can include a material shaping system, and the syncingfeatures can include shapes added to the processed material. The shapescan mechanically fit with a feed drive of the material depositionsystem. A cross section area of the processed material in a region ofthe shapes can be constant. For example, the shapes can be offsetchevron shapes.

The system of this aspect can further include the material depositionsystem. The controller can be coupled with and control the materialdeposition system. The system can further include a buffer for theprocessed material, the second system can have a controllable feed ratethat is coordinated with the input material feed rates, and the materialdeposition system can have a feed rate that is different than the feedrate of the second system. The feed rate of the second system can becontinuous, and the feed rate of the material deposition system can beintermittent.

The material deposition system can include an extruder nozzle and a feeddrive that syncs with the syncing features when delivering the processedmaterial to the extruder nozzle, and the second system can include ashaping system and a sizing system. The sizing system can be configuredto remove any extra material from the processed material and control across section area of the processed material with a standard deviationof less than 1% of a target value. Furthermore, the controller can beconfigured to create lengths of the processed material with continuouslyvariable composition ratios and with the syncing features placed inspecific locations along the processed material, the specific locationsbeing coordinated with the composition ratios, and the cross sectionarea of the processed material can be constant.

According to another aspect, a method includes independently controllinga feed rate for each of at least two different input materials for threedimensional (3D) printing to generate a processed material that variesin composition along its length; and add syncing features to theprocessed material, wherein the syncing features are useable by a 3Dprinter to synchronize the variation in composition of the processedmaterial during 3D printing of an object using the processed material.

Implementations according to this aspect may include one or more of thefollowing features. The method can include creating data usable by the3D printer to sync the processed material with volumetric or surfacelocations of the object during the 3D printing. The 3D printer caninclude a different fused deposition modeling (FDM) system, and creatingthe data can include creating the data in a data file usable by thedifferent FDM system. Moreover, the method can include controlling the3D printer to use the processed material including the syncing features;and creating lengths of the processed material with continuouslyvariable composition ratios and with the syncing features placed inspecific locations along the processed material, the specific locationsbeing coordinated with the composition ratios, and a cross section areaof the processed material can be constant.

One or more aspects of the subject matter described in thisspecification can also be embodied in a system for depositing materialwith controllable material properties, the system including: inputs forat least two input materials; an input material feed system withindependently controllable feed rate for each input material; a materialmixing chamber; an in-process material length; an output feed systemwith controllable feed rate; and an output orifice. The system caninclude an input feed controller; whereby the input feed controller isconfigured to communicate with each input feed system and controls theratio of feed rates of input materials whereby the composition ratio ofthe in-process material length can be controlled and continuouslyvaried. In addition, the system can include an output feed controller;whereby the output feed controller is configured to communicate with theoutput feed system and controls the feedrate of material through theoutput orifice.

The input feed controller and the output feed controller can becoordinated. The input feed controller and the output feed controllercan be the same controller. The system can include: a material shapingsystem with controllable feedrate coordinated with input materialfeedrates; wherein the material shaping system creates materialsynchronization features at controllable locations in the in-processmaterial length; and the output feed system includes feedsynchronization features; whereby the composition of the output materialcan be accurately controlled and synchronized with the output feed overtime.

The input materials can include at least three material colors and thecomposition ratio of material fed out of the output orifice can be aratio that can be continuously varied to any ratio of any of the atleast three input material colors. The system can include a materialsizing system configured to remove extra material and control the crosssection of the in-process material length with a standard deviation ofless than 1% of a target value. The synchronization features can beplaced so that the cross section area of the in-process material isconstant.

One or more aspects of the subject matter described in thisspecification can be embodied in a system for manufacturing materialwith continuously variable composition ratio including: inputs for atleast two input materials; an input material feed system withindependently controllable feed rate for each input material; an inputmaterial feed controller capable of independently specifying and varyingthe feedrate of each input material; a material mixing chamber in whichthe input materials mix with a controllable and variable ratio; and amaterial shaping system.

The material shaping system can create synchronization features in theoutput material at controllable locations; whereby lengths of materialcan be created with continuously variable composition ratio withsynchronization features placed in locations that are synchronized withspecific locations and coordinated with composition ratios. Thesynchronization features can be placed so that the cross section area ofthe material is constant. The system can include a material sizingsystem configured to remove extra material and control the cross sectionof the output material with a standard deviation of less than 1% of atarget value.

The details of one or more implementations of the subject matterdescribed in this specification are set forth in the accompanyingdrawings and the description below. Other features, aspects, andadvantages of the invention will become apparent from the description,the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example FDM 3D printing system.

FIG. 2A illustrates a side view of an example part made by FDM.

FIG. 2B illustrates a perspective view of the part of FIG. 2A.

FIG. 2C illustrates a cross section view of the example part of FIG. 2A.

FIG. 2D illustrates a top view of the part of FIG. 2A.

FIG. 3A shows a side view of an example part made by FDM according to animplementation of this disclosure.

FIG. 3B shows a cross section view of the part in FIG. 3A.

FIG. 4A shows a side view of another example part made by FDM accordingto an implementation of this disclosure.

FIG. 4B shows a cross section view of the part in FIG. 4A.

FIG. 4C shows a cross section view of the part in FIG. 4A.

FIG. 5 shows a cross section view of material deposited on a pre-madepart.

FIGS. 6A-6D show cross section views of example structures made by FDMaccording to another implementation.

FIG. 6E shows an isometric view of an example layer of the structures inFIGS. 6A-6D.

FIGS. 6F-6G show cross section views of example structures made by FDMaccording to another implementation.

FIG. 7 shows an idealized version of an example part.

FIG. 8A shows an example part made by FDM.

FIG. 8B shows a bottom perspective view of the part in FIG. 8A.

FIG. 8C shows a cross section view of the part in FIG. 8A.

FIGS. 9A-9I show various stages of an example interlocking materialdeposition pattern according to an implementation.

FIG. 9J shows an isometric view of an example completed part based onFIGS. 9A-9I.

FIG. 9K shows a top view of the completed part in FIG. 9J.

FIG. 10 shows an isometric view of an example part fabricated bydepositing material with FDM processes onto a prefabricated base part.

FIGS. 11A and 11B illustrate an example process of a milling machinemilling a slope with a ball endmill.

FIGS. 12A and 12B show a nozzle depositing material on a sloped surface.

FIG. 12C shows a cross section view and related geometries of the nozzleand sloped surface in FIGS. 12A-B.

FIG. 13 shows a flowchart of an example path creation method formaterial deposition according to an implementation of this disclosure.

FIGS. 14A and 14B show a nozzle depositing material on a sloped surfacewith a path determined by a control algorithm according to animplementation of this disclosure.

FIG. 15A shows a top view of an example desired part.

FIG. 15B shows a front view of the desired part.

FIG. 15C shows an isometric view of the desired part.

FIG. 15D shows a part shape divided into non-planar layers on top of abase part.

FIG. 15E shows a part shape divided into layers made up of materialdeposited along non-planar paths on top of a base part.

FIG. 15F shows an exploded view of the part construction of FIG. 15E.

FIG. 15G shows an isometric view of another example desired part.

FIG. 15H shows an isometric section view of a part shape divided intononplanar layers on top of a base part.

FIG. 15I shows an isometric section view of a part with non-planarlayers being fabricated by depositing material from a nozzle.

FIG. 15J shows a side view of a part with non-planar layers beingfabricated by depositing material from a nozzle.

FIGS. 16A-16F show examples of connector members and structures madewith connector members according to another implementation of thisdisclosure.

FIGS. 16G-L show an example inter-layer connection process.

FIGS. 17A-D show an example inter-linking process.

FIGS. 18A-D show another example inter-linking process.

FIGS. 19A and 19B show isometric views of an example structure andmethod for forming parts by material deposition according to oneimplementation.

FIG. 19C shows a front view of another example structure formed bymaterial deposition according this implementation.

FIG. 19D shows a front view of yet another example structure formed bymaterial deposition according to this implementation.

FIG. 20A shows an example of a system for fabricating 3D objects withcontinuously variable colors, material properties, or a combinationthereof.

FIGS. 20B-20C show details of the 3D printing system of FIG. 20A.

FIG. 20D shows a flow chart of an example of a process that can be usedwith one or more of the systems of FIGS. 20A-20C.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Referring to FIG. 1, an example FDM 3D printing system 100 includes anextruder or 3D printer 102, a controller 104, and a communication link106 that links the extruder 102 to the controller 104. The 3D printer102 includes an extruder nozzle 108. The FDM system 100 can produce 3Dproducts such as item 120. The controller 104 may include one or moreprocessors, memory, hard drive, solid-state drive, and/or inputs such astouch screen, mouse, or voice input capability. In some cases, thecontroller 104 may be an internet server or some other device, computer,processor, phone, or tablet. In some case, the controller 104 andextruder 102 are integrated into a single 3D printing device.

Referring to FIG. 2A, a 3D part 200 made by conventional FDM 3D printingtechniques is shown. As illustrated, layers 202 are planar andhorizontal. Layers 200 may be deposited sequentially starting with lowerlayer 204 first and proceeding upward one layer at a time until finallytop layer 206 is deposited. Layers 202 may be formed from athermoplastic material that is extruded from a heated nozzle (not shown)in the form of a filament that adheres to itself where it touches itselfalong its length within a particular layer 202 and where it touchesother layers. Only the outermost filament surfaces may be visible.

Each layer 202 may typically have a convoluted filament structure thattouches itself along its edges either continuously or at intervals tocreate a structure with desirable mechanical properties. However,adhesion at areas where the filament touches itself or other filamentlayers may not be sufficiently strong and may only be able to attain afraction of the breaking strength of a part made by molding or othertechniques where the material can be in solid form. In particular,inter-layer strength is typically lacking because layers 202 are onlyheld together by adhesion at relatively few or weak polymer bonds thatform during extrusion of one layer on top of the previous one and alsobecause there is no continuous filament material joining them. Partsmade by current state of the art FDM techniques, as a consequence, mayoften break or fail by layers coming apart or cracking. Parts may oftenstart to fail between layers, for example, merely due to thermalstresses inherently created as hot material deposited on top of coolermaterial layers then cools and either shrinks or remains affixed to theprevious layer but with internal stresses effectively stretching it tokeep it adhered to the other layers. These stresses may be strong enoughto cause layers to shear or peel away from one another or to warp thepart.

Referring also to FIG. 2B, the part 200 has a curved or domed form.Here, each layer 202 effectively forms a horizontal slice of the desiredshape and together with other layers 202 form an imperfect approximationof the desired 3D form.

In the cross section view of FIG. 2C, more of the filament structure oflayers 202 can be seen. Here, edge filaments 208 approximate the idealcross section 220 of the part 200. Edge filaments 208 have a circular,oval, or rounded rectangular cross section shape which is typical of thecross sectional shape of the filament material elsewhere in the part.Bottom layer 204 has an internal filament structure inside the boundarycreated by its respective edge filaments 208 that runs largely parallelto the cutting plane used to create this cross section view. Thusinternal filament 210 for this layer appears to run continuously fromone edge filament 208 to the other. A second layer 212 has similar edgefilaments 208 and has internal filaments 210 running largelyperpendicular to the cross section plane. Subsequent layers alternatethe direction of their internal filaments. In this view, the part 200 isshown to be largely solid, except for small voids between filaments. Inpractice, parts may also have voids intentionally built into theirinternal filament structure to reduce mass or filament material used. Asillustrated, the top layer 206 has a distinctly flat top face 214 thatdoes not match the ideal cross section 220 very well.

FIG. 2D shows a top view of the part 200. The full filament structure oftop layer 206 can be seen. The top layer 206 includes an edge filament208 and an internal filament 210. Internal filament 210 can follow azig-zag path so that it touches itself along most of its edges. Eventhough the desired form of the part 200 is curved in all directions inthe vicinity of top layer 206, the top layer 206 has a discrete flat,planar top face 214. The flatness and other artifacts of thediscretization or approximation of a desired shape by flat layer slicesare often aesthetically undesirable and/or functionally undesirable orintolerable.

The shape artifacts of flat layers and the inter-layer weakness inherentto flat layers, as discussed above, often prevent FDM from being used tomake components or products even though it may be a cost effectivemanufacturing technique. If the negative consequences of these flatlayers could be eliminated or mitigated, many more components andproducts could be feasibly manufactured via FDM and thus enable greateconomic and other benefits such as on-demand manufacturing, eliminatinginventory cost, product customization and bespoke products, localizedmanufacturing, reduced or eliminated shipping, eliminating unwanted orsurplus product inventory problems, achieving a greater degree ofproduct recyclability and material reuse, creating local, direct productrecycling and material reuse. To address some of the problems withconventional FDM techniques described above, implementations of newtechniques and improvements are described below.

FIGS. 3A and 3B show a part 300 made by FDM with improved toolpathtechniques according to an implementation of the current disclosure.Here, a flower-shape is shown. FIG. 3A shows a side view of the part300, and FIG. 3B shows a cross section view of the part 300. Visible inFIG. 3A is an outer non-horizontal shell of filaments 302, which mayalso be non-planar. Generally, non-planar layers may be created vianon-planar relative motion (e.g., relative motion in all three axes) ofan extruder or other material deposition system relative to the part 300so that the form of shell filaments 302 more closely matches the desiredpart shape than does the part 200 of FIGS. 2A-2C. Shell filaments 302may also incorporate decorative and/or structural filament patterns 304.In FIG. 3B, one possible arrangement of the underlying filament layers306 is shown. Underlying layers 306 may be similar to or identical tothe flat layers 202 of FIGS. 2A-2C. As illustrated, the shell 302crosses and adheres to underlying layers 306. It therefore ties allunderlying layers 306 together and helps to reduce or eliminate theaforementioned weakness of the part 200 in which underlying layers areonly connected by weak inter-filament bonds that can peel apart. Theshell 302 reinforces the part 300 particularly across internal layers306 to make the part 300 much stronger.

Compared to the part 200 shown in FIGS. 2A-2C, the part 300 has thefollowing benefits: 1) it is much stronger and more mechanically robust;2) it more closely matches the ideal or intended part shape; and 3) itmay contain decorative and structural filament patterns on its exteriorwhich are not constrained to be planar and which can better meet theaesthetic, structural and functional requirements for a given part.

FIG. 4A shows a side view of another example part 400 made by FDM withimproved toolpath techniques. In this case, a triangular-spiral designhas been implemented. FIG. 4B shows a cross section view of the part400. The part 400 has one or more outer non-planar shells of filaments402, which are created by non-planar motion of an extruder or othermaterial deposition system so that the form of shell filaments 402closely matches the desired part shape. The part 400 is similar to part300 of FIGS. 3A-B except that it shows a different filament pattern orarrangement in shell 402. Underlying layers 404 are visible in FIG. 4B.The pattern of filaments 402 in this case has been designed to regularlycross underlying layers 404 in a direction which best reinforces acrosslayers 404.

FIG. 4C shows an a part 406, which differs from part 400 in that it hasmultiple filament shells 408 which are similar to shell 402. Two layers408 are shown, but three, four, five, or nearly any number of shells arepossible in practice. A set of internal flat layers, which may or maynot be needed, may be reinforced by shells 408.

Referring now to FIG. 5, a part 500 is formed by applying filaments 502to a base part 504. The base part 504 may be a pre-made molded part or apart made by another 3D printing technique such as SLS (selective lasersintering) or SLA (stereolithography) or it may be made by some otherplastic manufacturing method or it may be wood or metal or some othermaterial. The base part 504 may be a mass-produced part where manyidentical base parts are produced, or the base part 504 may be a unique,bespoke, or custom part. Filaments 502 may be applied after the basepart 504 is made. The pattern of filaments 502 may be custom, unique, orbespoke even if base part 502 is mass-produced. In this way, customizedparts are possible which take advantage of the low cost of injectionmolding for most of the mass and/or volume of the part. This also hasthe advantage of making available multiple materials and multiple colorsin a single part which are difficult or sometimes impossible to achievein an injection molded part. For example, filaments 502 may be anelastomer material formed in continuously variable color or full coloron top of a rigid molded polymer base part 504. This technique can alsogreatly simplify product designs by allowing multiple parts to becombined into a single component and enabling geometries that cannot beproduced by molding, machining or other traditional manufacturingtechniques. The combined processes may be automated so that base parts504 may be produced automatically by molding or other mass productionmethods and then each base part 504 may be transferred to an FDM systemautomatically where filaments 502 may be automatically applied, allwithout specific human attention or intervention. Packing and shippingprocesses may also be automated.

In some cases, the base part 504 may be made bespoke and made via SLS orsome other 3D printing method or direct manufacturing method. 3Dprinting methods such as SLS, SLA, direct metal laser sintering (DMLS),and several others are typically limited to a single material per partbut may offer high resolution for fine details. By adding filaments 502in different colors and/or materials to the base part 504 made by adifferent 3D printing method or direct manufacturing method such asmachining, fully custom parts can be produced which take advantage ofthe strengths of one technique for the base part 504 such as excellentyield strength via SLS and also still have the ability to have multiplecolors and materials. The combined processes may be automated so thatthe base part 504 may be produced automatically and transferred to anFDM system automatically where filaments 502 may be automaticallyapplied, all without specific human attention or intervention. Packingand shipping processes may also be automated.

In some cases, filaments 502 may be produced first, and if they encloseor define a volume, then filaments 502 may serve as a mold so that basepart 504 may be cast or formed in-place afterward. A molding or formingprocess for creating base part 504 with filaments 502 already in placemay optionally also employ additional mold core(s), inserts or othermold components (not shown). The process of creating the pattern offilaments 502 may also optionally involve a separate form (not shown),so that filaments 502 are made over a form, then removed before basepart 504 is formed onto them. Other variations of this process are alsopossible. This process may be automated so that filaments 502 may beformed automatically and then base part 504 may be formed into themautomatically so that the entire process is automatic and requireslittle or no human attention or intervention.

In some cases, the base part 504 may be made of a dissolvable ormeltable material so that after processing of filaments 502 is complete,the part 500 may be removed and the base part 504 may be dissolved ormelted away to leave behind only filaments 502. The base part 504 mayalso be printed in the form of dissolvable filaments to achieve thisresult.

In some cases, the base part 504 may be made of several parts which forma collapsing core so that when processing of filaments 502 is complete,a first part of the base part 504 may be removed which then leaves spaceto allow other parts of the base part 504 to collapse inward indirections appropriate for allowing them to separate from the portion offilaments 502 that they supported. This technique may be particularlyuseful if filaments 502 take on a shape with undercuts or protuberances.In such a case, the collapsing core technique can allow the part 504 tobe removed where a solid base part would not be removable.

In some cases, the base part 504 may be made of wood or other naturalmaterials. Alternatively, the base part 504 may be a temporary“programmable” support structure composed of an array of pin, shaft, orprism shapes which may be individually adjusted up or down, each to aspecified position. Pins or shafts may be pushed down into individualpositions by the nozzle of an FDM system. If base part 504 is aprogrammable support structure, it may be removed from filaments 502 andreprogrammed or reshaped and reused as a support to make additionalsimilar or different parts.

In some cases, the base part 504 may be rotated as filaments 502 areapplied to allow creation of different shapes than would be possible ifbase part 504 remains in a fixed orientation. In particular, the basepart 504 may be rotated about an axis that is not vertical or an axisthat is horizontal or some other angle which allows filaments 502 to bedeposited on a larger portion of base part 504 or even the entiresurface of base part 504. Alternatively, or additionally, the materialdeposition nozzle may be rotated so its axis does not stay vertical asfilaments 502 are deposited so that filaments 502 may be deposited inpatterns not possible with a vertical nozzle. This type of rotation ofthe material deposition nozzle is possible with additional axes on aprinter such as a 4, 5 or 6 axis printer.

Referring now to FIG. 6A, a cross section view of an FDM filamentarrangement 600, made based on another implementation of an FDM processaccording to the present disclosure, is shown. FDM parts can suffer frominter-layer (vertical) weakness because filament polymer chains onlyweakly interlink between layers. In contrast, as shown, the filamentarrangement 600 vertically links, or interlocks, layers together tocreate stronger parts. The filament arrangement 600 includes a topfilament 602 which has a protruded portion 604, a first lower layer 606which has a first gap 608, an optional second lower layer 610 with asecond gap 612, and an optional base layer 614. An FDM process forproducing vertically interlinked layers involves optionally firstdepositing base layer 614 if needed, then depositing layer 610 on top ofbase layer 614 (if present), and leaving gap 612, then depositing layer606 on top of layer 610 and leaving gap 608, then depositing filament602 and pausing or slowing horizontal motion of the extruder whileextruding extra material to form the protruded portion 604 which fillsthe gaps 608 and 612 and locks filament 602 to layer 606 and to a lesserextent, layer 610. The gap 612 may be larger than gap 608 or offset fromit so that the protruded portion 604 has a wide portion 616 which iswider than gap 608 so that portion 616 may not pass through gap 608 evenif inter-layer bonds between the filament 602 and the layer 606 fail.The protruded portion 604 is formed with molten or soft material whichsubsequently hardens or solidifies. For clarity, gaps 608 and 612 areshown leaving space around the protruded portion 604, but in practicethe protruded portion 604 may form tightly against the perimeter of gaps608 and 612 leaving little or no space. One instance of filamentarrangement 600 is shown, but a part may contain many such arrangementsand any given material layer may incorporate protrusions such as 604,gaps such as 608 and gaps such as 612 so that all layers may bevertically linked together.

FIG. 6B shows a part 618 including eight layers 620. As shown, the part618 includes six instances of interlocked filament arrangements 600which link the top six layers 620 together.

FIG. 6C shows a filament arrangement 622 which is a variation of thearrangement 600. In filament arrangement 622, a protruded portion 624 isshown having a lumpier shape than the protruded portion 604 of FIG. 6A.Despite the variation in the shape of the two protrusions, theinterlocking function works similarly.

FIG. 6D shows a filament arrangement 626 which is similar to arrangement600 except that three gap layers 628 are shown and a protruded portion630 physically interlocks with the upper two of layers 628 rather thanjust a single layer interlock as in arrangement 600. An optional upwardprotrusion 632 may be remelted and its polymer chains more effectivelylinked to an upper adjacent layer (not shown) by physical mixing as theextrusion nozzle moves over protrusion 632 to deposit the upper adjacentlayer.

FIG. 6E shows an isometric view of one layer 634 of a part made withimproved toolpaths for FDM as discussed in FIGS. 6A-D. One or moreboundary filaments 636 are used to create a structural and potentiallyaesthetic outer boundary with few or no gaps. Inner filaments 638 fillsome portion of the interior space and primarily serve to createstructural integrity. Filaments 638 may take a variety of lengths,shapes, or forms. Filaments 638 are shown here as straight segments, butthey may be curves or some other shape volumes created by depositingmaterial. Defined at intervals between filaments 638 are gaps 640. Gaps640 provide locations where extra material can flow or be deposited fromabove, typically as the next layer is being created, so that additionalvertically stacked layers will be physically interlocked.

FIG. 6F shows a cross section view of a different interlocking structurearrangement 642. The structure 642 is formed as a set of layers 644. Aset of connector segments 646 is formed with each additional segment 646being added as a new layer 644 is added to structure 642. Each connector646 includes a protruded portion 648 that protrudes above thesurrounding material of that layer. As each connector 646 is formed, anextrusion nozzle (not shown) remelts the protruded portion 648 of theunderlying connector and may move in a repetitive path over it whileextruding more material. Thus, material from the previous connector isremelted and inextricably mixed with new material that is deposited forthe new connector. This process enables connector segments 646 tofunction as a structurally integral unit, linking layers 644 together.Connectors 646 are formed from molten material which also flows to takeon the shape of layers 644 which serves to enhance the vertical linkingof layers 644. Just the connectors 646 are shown in FIG. 6G for improvedclarity.

Referring now to FIG. 7, an ideal 3D part 700 including graphic designelements 702 is shown. Design of the part 700 is difficult to realizewith current FDM techniques both in terms of function and aesthetics.

For example FIG. 8A illustrates a typical part 800 created using currentFDM techniques and toolpath planning using the geometry of the part 700as input to the path planning process. As shown, the part 800 is builtas a series of vertically stacked horizontal layers 802. The lowerportion of part 800 has vertical sides so layers 802 reasonablyapproximate the ideal shape. Upper portion of part design 800, however,has a gentle arcing sloped shape. The sloped shape when approximated bydiscrete FDM layers 802 creates a stair-stepped surface 804 which is anon-ideal representation of the design intent of part 700. Anothershortcoming of part 800 is inter-layer strength. Because layers 802 areformed sequentially, each on top of the previous one, there is nomechanical interconnection to improve inter-layer strength.

Typically a relatively poor degree of cross linking between polymerchains may be achieved at the interface between layers as compared withthe polymer cross linking in the bulk material within each layer. Thismay result in layers that can pop apart or shear at their junctions withmuch less force than if the part was molded in a similar shape with asimilar amount of material.

FIG. 8B shows an underside view of part 800 which shows that the part ishollow and shows the inside walls of layers 802. Inter-layer weaknessmay be a particular problem for a part such as this with thin walls.FIG. 8C shows a cross section view of part 800 which clearly illustratesthe stair-step nature of surface 804.

Referring now to FIG. 9A, a structural filament element 900 may berepeated to form an interlocking structure. Filament element 900 has alower extension 902 with protruding tabs 904. Filament element 900 maybe formed by extruding material through a moving nozzle (not shown).Lower extension 902 can be formed by having the nozzle pause its motionwhile continuing to extrude material into a gap in elements below (notshown).

FIG. 9B shows an interlocking structure 906 made up of interlockingfilament elements 900 plus additional supporting filament elements 908.Tabs 904 of one element 900 extend and interlock under adjacent elements900 and 908. Structure 906 is built in layers 910 which are mechanicallyinterlocked so that inter-layer weakness shown in FIGS. 8A-C is reduced.

FIG. 9C shows a partial single layer 912 of interlocking filamentelements 900 and supporting filament elements 908 as they would beformed by an extruder moving around to deposit material on one layer ofa part.

FIG. 9D shows a complete single layer 914 of filament elements 900 and908 with surrounding inner perimeter filament 915 and external perimeterfilament 916.

FIG. 9E shows partial layer 912 with a next partial layer 918 applied ontop of it. Both layers are made up of interlocking filament elements 900and supporting structural elements 908.

FIG. 9F shows complete layers 920 and 922 with internal perimeterfilaments 915 and external perimeter filaments 916.

FIG. 9G shows interlocking partial layers 924 being formed by a movingextruder nozzle 926. Nozzle 926 is shown forming a next layer offilament elements 900 and 908. External and internal filaments are notshown for clarity.

FIG. 9H shows a larger structure of interlocking layers 924. Externaland internal filaments are not shown for clarity. Gaps 932 are visible.

FIG. 9I shows a structure of complete interlocking vertical layers 924with external perimeter filaments 916 and internal perimeter filaments915 shown. Perimeter filaments 915 and 916 serve to create smooth,structural inner and outer surfaces. Gaps 932 are visible. Gaps 932 areprovided for anchoring the next layer to be applied above.

FIG. 9J shows a completed part 928 made with improved FDM techniques andpaths. Part 928 includes interlocking vertical layers 924 and non-planarupper surface filament pattern 930. In contrast to the stair-stepsurface 804 of FIG. 8A, filament pattern 930 more closely follows theideal shape of part design 700 of FIG. 7. Additionally, filament pattern930 includes shaped filaments 934, which are designed to follow theshape of graphic design elements 702 of ideal part design 700. Pattern930 and shaped filaments 934 may include filaments of different colorsand/or materials and are therefore able to represent visual graphicpatterns much better than current FDM techniques.

FIG. 9K shows a top view of the completed part 928. Shaped filaments 934include non-uniform width filaments 936. Filaments 936 have non-uniformcross section, even though they may have uniform thickness. Filaments936 are created by depositing material along a path with a materialdeposition flowrate that varies along the path or profile of thefilament. The material deposition flowrate is determined by a pathplanning algorithm that dynamically changes the flowrate according tothe instantaneous, changing area of the filament to be created along thepath.

FIG. 10 shows a part 938 created by applying filaments 940 to a basepart 942. Filaments 940 may be applied by an FDM process. Base part 942may be a pre-made molded part or a part made by another 3D printingtechnique such as SLS (selective laser sintering) or SLA(stereolithography) or it may be made by some other plasticmanufacturing method or it may be wood or metal or some other material.Base part 942 may be a mass produced part where many identical baseparts are produced, or base part 942 may be a unique, bespoke, or custompart. Filaments 940 may be applied after base part 942 is made. Thepattern of filaments 940 may be custom, unique, or bespoke even if basepart 940 is mass-produced.

Referring now to FIGS. 11A and 11B, FIG. 11A illustrates a cross sectionview of a typical process of a milling cutter 1102 milling a part 1104to create a desired sloped surface shape 1106. The cutter 1102 may spinabout an axis 1118. In some cases, the milling cutter 1102 may be a ballendmill as shown in this figure. A ball endmill is a milling cutter thatnominally cuts a semi-spherical shape when rotated in contact with apart. Milling cutter 1102 may be held in a holder.

As illustrated, an initial material surface 1110 is being removed by thecutter 1102 as it moves over the part 1104 with a direction of motionindicated by an arrow 1105 in the figure. Initial material surface 1110is removed to create a desired surface shape 1106. To create the desiredsurface shape 1106, the cutter 1102 is moved such that a reference point1116 follows a path 1112. In this case reference point 1116 lies at thecenter of the effective spherical shape of the end of the cutter 1102,and the path 1112 is chosen such that the reference point 1116 maintainsa constant normal offset distance 1114 from the desired surface shape1106. Distance 1114 is measured normal to (perpendicular to) the desiredsurface shape 1106. The position of the cutter 1102 may also bemeasured, planned, or tracked as distances or coordinates from an origin1111, for example based on a vertical coordinate 1113.

In FIG. 11A, the cutter 1102 is shown travelling along the path 1112which goes “downhill,” i.e., in a downward sloping direction, as isconventionally done. Cutters may have different shapes such as flatendmills, bull-nose endmills, form cutters (such as chamfer cutters andogee shapes), among others. In all such cases, a path similar to thepath 1112 is created so that the cutter is moved such that the point onthe cutter that protrudes the farthest toward the part when measured ina direction orthogonal to the desired surface (going from the cuttertoward the desired surface) follows the desired surface. For some cuttershapes such as bull-nose endmills, the point on the cutter that createsthe desired surface or the reference point used to create the path maychange along the path trajectory.

FIG. 11B illustrates a cross section of the cutter 1102 milling adesired surface shape 1106 on a different portion of the part 1104.Here, the cutter 1102 is moving “uphill,” i.e., moving along an upwardslope in FIG. 11B along an arrow 1107. The cutter 1102 is shown removingan initial material surface 1120 in order to create the desired surfaceshape 1106. However, the cutter 1102 is moving uphill in FIG. 11Bwhereas it was moving downhill in FIG. 11A. The cutter 1102 travelsalong a path 1122 that maintains a constant normal distance 1114 betweenthe desired surface shape 1106 and the reference point 1116 on cutter1102. The path 1122 in FIG. 11B showing uphill motion of cutter 1102 tocreate desired surface shape 1106 may have the same path shape as path1112 of FIG. 11A in which the cutter 1102 moves downhill to create thesame desired surface shape 1106. The shapes of path 1122 and path 1112may be the same even though the direction of motion of the cutter isdifferent. The direction of motion, uphill or downhill therefore doesnot affect the shape of the required path to create a desired surfaceshape with a spinning milling cutter such as 1102.Direction-independence of path shape is true regardless of the shape ofthe spinning milling cutter.

Subtractive processes, such as the milling processes of FIGS. 11A and11B, were the standard method of creating bespoke surface shapes priorto the advent of additive manufacturing such as 3D printing. Additiveprocesses such as 3D printing have thus far primarily added material inhorizontal planar layers. However, there may be advantages to addingmaterial in non-horizontal or non-planar layers or other non-planarstructures. The path planning for additive manufacturing and materialdeposition processes with non-horizontal paths and non-horizontaldesired surfaces may be different than path planning for subtractiveprocesses such as milling of non-horizontal paths and desired surfaceshapes to achieve desired or optimal results.

Referring now to FIG. 12A, a nozzle 1202 is shown depositing material1204 on a sloped part surface 1210 with a motion of travel in a downwardsloping direction along part surface 1210. The nozzle 1202 may be anozzle or it may be a different material deposition system such as awelding tip or electrode, syringe, adhesive material deposition system,material solidification system, material curing system or material pump,or combinations thereof. A material deposition process shown in FIG. 12Aresults in a deposited material shape 1208. The nozzle 1202 has an exitorifice 1216 with an orifice exit dimension 1220. Orifice exit dimension1220 may be a diameter or it may be a width dimension if exit orifice1216 is non-circular. The nozzle 1202 has a nozzle tip outer dimension1222, which may be greater than orifice exit dimension 1220. Nozzle tipouter dimension 1222 may be an outer diameter if the tip of the nozzle1202 is circular (i.e., if the nozzle 1202 is a revolved shape such ascone or cylinder), or it may be a width dimension if the tip of thenozzle 1202 is non-circular. An arrow 1205 indicates the direction ofmotion of the nozzle 1202 relative to part surface 1210. In practice,the nozzle 1202 may move or part surface 1210 may be moved orcombinations thereof to create relative motion. A reference point 1214is shown at the center of a material exit orifice 1216. In conventionalmaterial deposition, 3D printing processes and additive manufacturing,material is typically deposited in horizontal, flat layers, or planes.

In conventional material deposition processes, a nozzle is typicallymoved such that a reference point such as point 1214 is moved at aconstant distance away from a surface such as part surface 1210 thatmaterial is being deposited onto. In conventional material depositionprocesses, the distance away from the surface onto which material isdeposited, and therefore the path of nozzle motion, is independent ofdirection, similar to the way that distance 1114 isdirection-independent in FIGS. 11A and 11B. The position of the nozzle1202 may also be measured, planned, or tracked as a vertical distance1232 from part surface 1210 or as a horizontal coordinate (not shown)and a vertical coordinate 1240 representing a vertical distance from anorigin 1242. A desired material shape 1212 is shown in FIG. 12A as adashed line. A resulting deposited material thickness 1209 is alsoshown. As illustrated, the nozzle 1202 is being moved along a path suchthat a distance 1218 from reference point 1214 to part surface 1210 isindependent of whether the nozzle 1202 is moving uphill or downhill,i.e., independent of the slope of the path followed by the nozzle 1202.As a result, deposited material shape 1208 does not match desiredmaterial shape 1212, and the resulting deposited material thickness 1209is not correct, i.e., is not equal to a desired result. This variationmay occur because, as illustrated, a portion of the nozzle 1202 scrapesthe depositing material 1204 as it exits the exit orifice 1216.

FIG. 12B shows the nozzle 1202 depositing material 1204 on the slopedpart surface 1210 with a motion of travel in an upward direction alongthe part surface 1210. The nozzle 1202 is the same as the nozzle 1202 ofFIG. 12A except that the nozzle 1202 is now shown moving uphill relativeto the part surface 1210 instead of downhill as in FIG. 12A. The nozzle1202 may be a nozzle or it may be a material deposition system such as awelding tip or electrode, syringe, adhesive material deposition system,material solidification system, material curing system or material pumpor combinations thereof. A material deposition process shown in FIG. 12Bcan result in a deposited material shape 1224.

FIG. 12B shows an arrow 1207 to indicate the direction of motion of thenozzle 1202 relative to the part surface 1210. In practice, the nozzle1202 may move or the part surface 1210 may be moved or combinationsthereof. The desired material shape 1212 is shown as a dashed line. InFIG. 12B, the nozzle 1202 is being moved along a path such that distance1218 from reference point 1214 to part surface 1210 is independent ofwhether the nozzle 1202 is moving uphill or downhill, i.e., independentof the slope of the path that the nozzle 1202 is moving along. As aresult, deposited material shape 1224 does not match desired materialshape 1212. In addition, deposited material making up shape 1224 may notmeet or adhere well to part surface 1210 and may leave a gap 1226between material shape 1224 and part surface 1210. The resultingdeposited material shape 1224 of FIG. 12B created when the nozzle 1202deposits material 1204 while moving uphill is different than thedeposited material shape 1208 of FIG. 12A that is created when thenozzle 1202 deposits material 1204 while moving downhill, despite thepath followed and distance 1218 from part surface 1210 to nozzlereference point 1214 being the same in both cases. The material shapecreated by a material deposition process on a non-horizontal surface orpath may therefore be dependent on the direction of motion of a nozzleor deposition system or the sign (positive, zero or negative) of theslope of the path followed by the nozzle or material deposition system.This slope or direction dependency of the final result is different thanconventional subtractive processes such as milling and also differentfrom conventional additive manufacturing processes such as FDM in whichmaterial is deposited in horizontal layers and the thickness of theresulting material is generally not path, slope, or direction dependent.The path of the nozzle 1202 may also be measured with respect to thedesired part shape 1212 rather than the part surface shape 1210; theresulting conclusions of path and slope dependency and resultingdeposited material shapes are the same.

Referring also to FIG. 12C, a cross section view of a generalizedmaterial deposition system 1227 is shown. The nozzle 1202 may have around, cylindrical, or conical or rotated form, or it may have atriangular, square, hexagonal or prismatic form. The part surface shape1210 has an angle 1228 relative to horizontal. The nozzle 1202 may alsohave an effective shape angle 1230 relative to horizontal. Angle 1230may in practice be any angle, but for the purposes of this example maybe greater than or equal to angle 1228 so that a proximal point or edge1244 on the nozzle 1202 which is the closest to part surface 1210 is ata closest edge of nozzle tip dimension 1222. As in FIGS. 12A and 12B,nozzle reference point 1214 lies at the center of the nozzle exitorifice 1216. The position and path of the nozzle 1202 may be measured,tracked, or planned according to the distance 1218 between referencepoint 1214 and part surface 1210 measured normal to (perpendicular to)part surface 1210 as in FIGS. 12A and 12B. Also as in FIGS. 12A and 12B,distance 1232 represents the vertical distance between point 1214 andpart surface 1210. The position and path of the nozzle 1202 may also bemeasured, tracked, or planned via distance 1232. A distance 1234represents a vertical distance from point 1244 to part surface 1210. Adistance 1236 represents the difference between distance 1232 anddistance 1234, which may also correspond to the difference between thevertical distance between the center of the tip of the nozzle 1202 andpart surface 1210 and the vertical distance between closest point 1244on the tip of the nozzle 1202 and part surface 1210. A distance 1246represents the vertical distance between a distal point or edge 1248 onnozzle exit orifice 1216 that is the farthest point on nozzle exitorifice 1216 from part surface 1210. A distance 1238 represents thedifference between distance 1246 and distance 1232, which may also bethe difference between the vertical distance of the center of the tip ofthe nozzle 1202 and part surface 1210 and the vertical distance of thefarthest point on exit orifice 1216 to part surface 1210.

The geometry of the system 1227 as illustrated in FIG. 12C may be usedto calculate correction factors for the position and path of the nozzle1202 or other material deposition system such that with correctionfactors applied, the resulting deposited material thickness may besimilar or the same when the nozzle travels downhill or uphill orhorizontally. In one method of correcting the position or path of thenozzle 1202, corrections may be made in the following way: a firstnominal path or set of positions for the nozzle 1202 is computedindependent of the direction of travel of the nozzle 1202 or the slopeof the path of the nozzle 1202. The first nominal path may be similar orequal to path positions represented by dimension 1218 in FIGS. 12A and12B and may be calculated by finding positions or a path for the nozzle1202 such that dimension 1218 is kept constant along the first nominalpath. Then a second path may be created by adjusting vertical positionvalues (such as dimension 1232 or coordinate 1240 in FIG. 12A) by anamount dependent on the slope of the path of the nozzle 1202. The slopeof the path may be defined as vertical distance moved over an intervaldivided by horizontal distance moved over the same interval, or as rateof instantaneous vertical motion divided by rate of instantaneoushorizontal motion.

When the nozzle 1202 is travelling downhill, i.e., when its path has anegative slope, the vertical position of the nozzle 1202 at points alongthe second path may be adjusted such that a corrected version ofdistance 1234 may be equal to the dimension 1232 from respective pointsin the first nominal path. This is because when the nozzle 1202 travelsdownhill, the point 1244 may determine the thickness of the resultingdeposited material.

When the nozzle 1202 is travelling uphill, i.e., when its path has apositive slope, the vertical position of the nozzle 1202 for the secondpath may be adjusted such that the corrected distance 1246 for thesecond path may be equal to the dimension 1232 as calculated for eachpoint in the first nominal path. This is because when the nozzle 1202travels uphill, the distal edge of the nozzle exit orifice asrepresented by the location of point 1248 may determine the thickness ofthe resulting deposited material.

In the case of downhill motion, a vertical coordinate or distancerepresenting the vertical position of the nozzle 1202 in the second pathmay be found by adding the absolute value of dimension 1236 ascalculated for each point of downhill (negative) slope on the firstnominal path to dimension 1232 for each point on the first nominal pathor to whatever other vertical coordinate is used for the first nominalpath. The resulting second path will then be higher by an amount equalto the absolute value of dimension 1236 in areas with downhill slope.

In the case of uphill motion, a vertical coordinate or distancerepresenting the vertical position of the nozzle 1202 in the second pathmay be found by subtracting the absolute value of dimension 1238 ascalculated for each point of uphill (positive) slope on the firstnominal path from dimension 1232 for each point on the first nominalpath or from whatever other vertical coordinate is used for the firstnominal path. The resulting second path will then be lower by an amountequal to the absolute value of dimension 1238 in areas with uphillslope.

In the case of zero slope (horizontal motion), no correction may beapplied or a correction factor of zero may be found and subtracted fromthe first nominal path using the uphill calculation case with dimension1238 equaling zero or the downhill calculation case with dimension 1236equaling zero.

After the corrected path points have been found for points or regions ofnegative slope, positive slope and zero slope, the points or pathregions may be combined in their respective path order to form acompleted second path.

In some cases, the second path may be adjusted only for points thatcorrespond to negative slope (i.e., without adjusting for points thatcorrespond to positive slope). Alternatively, in some cases, the secondpath may be adjusted only for points that correspond to positive slope(i.e., without adjusting for points that correspond to negative slope).

In more detail, any two adjacent positions of the nozzle 1202 along apath of travel may be represented as cartesian coordinates (X1, Y1, Z1)for a first point and (X2, Y2, Z2) for a second point. The relativedistance delta.XY between point1 and point2 as projected in the X-Yplane may be calculated as: delta.XY=SQRT((x2−x1)̂2+(Y2−Y1)̂2). Then forpoints where the path has negative slope, dimension 1236 which is usedas the correcting factor between the first nominal path and the secondpath in areas of negative slope may be calculated asdimension_1236=ABS(((Z2−Z1)*dimension_1222/2)/delta.XY). Because thepath has a negative slope in this case, the absolute value function isused to ensure a positive value for dimension 1238. For points where thepath has positive slope, dimension 1238 which is used as the correctingfactor between the first nominal path and the second path in areas ofpositive slope may be calculated asdimension_1238=((Z2−Z1)*dimension_1220/2)/delta.XY. Because the path hasa positive slope in this case, Z1 will be less than Z2 and thiscalculation will yield a positive value for dimension 1238.

Another way to calculate a correction factors dimension 1236 and 1238 isto use the trigonometric tangent of angle 1228, where angle 1228 isdefined as negative for downhill nozzle motion (negative slope) as shownin FIG. 12A and positive for uphill motion (positive slope) as shown inFIG. 12B. An alternate corrected value calculation for dimension 1238for points of negative slope on a path for the nozzle 1202 may then beexpressed as (−1*(dimension_1222/2)*tan(angle_1228)). An alternatecorrected value calculation for dimension 1238 for all points on a pathfor the nozzle 1202 with positive slope may then be expressed as:dimension_1238=(dimension_1220/2)*tan(angle_1228)).

A first partial second path consisting of corrected values for distance1232 may be calculated for points with negative slope on the path of thenozzle 1202 as: distance_1232_corrected=distane_1232_from first nominalpath+dimension_1236. A second partial second path consisting ofcorrected values for distance 1232 may be calculated for points withpositive or zero slope on the path of the nozzle 1202 as:distance_1232_corrected=distance_1232_from first nominalpath−dimension_1238. The first partial second path and second partialsecond paths may then be combined to create a complete slope-correctedsecond path.

A second corrected path may also be calculated using any verticalcoordinate or representation of vertical distance for each point inplace of dimension 1232, for example vertical distance 1240 to an origin1242 in FIG. 12A may be used in which case an alternate corrected pathcalculation may be distance_1240_corrected=distance_1240_from firstnominal path+dimension 1236, for areas of negative slope, anddistance_1240_corrected=distance_1240_from first nominalpath−dimension_1238, for areas of zero or positive slope.

The second path or set of positions as calculated by any of the methodsabove or combinations thereof may then be used to guide the nozzle 1202to deposit material on sloped or horizontal part surfaces and mayachieve a more constant resulting thickness of deposited materialregardless of the slope of part surface 1210 and may also achieveimproved adhesion of deposited material. This is an improved resultcompared to the inconsistent thickness of resulting deposited materialshown in FIGS. 12A and 12B and the possible poor adhesion or gap 1226 asshown in FIG. 12B. Additional correction factors may also be applied,for example points on paths with positive slope may be adjusted downwardeven more by subtracting an optional base amount times an optionalfactor times the positive slope value from the Z coordinate values ofpoints in the second path in order to promote further improved adhesionwhen the nozzle 1202 is traveling along a path with positive slope.Paths with upward, downward, or horizontal slopes may be furtheradjusted upward or downward to change or improve surface finish,texture, fill factor, density or fusing of deposited material.Additional adjustments may be made by calculating a third path or byincluding the calculations along with the initial slope adjustments inthe process of creating the second path. Path adjustments do not need tobe symmetric for paths of positive and negative slopes. Improvements todeposited material thickness, adhesion, surface finish, texture, fillfactor, density, and material fusing may be obtained by adjusting pathswith positive slopes differently than paths with negative slopes.

The calculation of correction factors for the position and path of thenozzle 1202, as described in the implementations above, may be performedand implemented by the controller 104. In some cases, a separate pathplanning system may perform the calculation of the correction factorsand generate corresponding machine control instructions for controllingthe movement path of the nozzle. The controller 104 may then receive andinterpret such instructions, which incorporate the correction factors,and implement them by controlling the nozzle to move accordingly. Insome cases, a data transfer system may be used to transfer the generatedmachine control instructions from the path planning system to thecontroller. The path planning system may be, for example, a separatecomputer that calculates the correction factors and the resulting nozzlepath prior to the fabrication process.

FIG. 13 shows a flowchart 1250 of an example of an algorithm for pathcorrection and improved material adhesion for a material depositionsystem. In step 1252, a first nominal path is calculated independent ofsurface slope. The first nominal path may be made up of discrete pointsor it may include mathematical functions such as spline curves,polynomial curves, piecewise math functions, continuous math functions,or combinations thereof. Discrete points may be 3D Cartesiancoordinates, or they may be 2D Cartesian coordinates. In some cases, thediscrete points may be polar coordinates or spherical coordinates, orthey may be 4D, 5D, 6D or higher level dimension coordinates, forexample with additional dimensions containing information aboutextrusion ratio, color, material, density, rotational axis position,second rotational axis position, gimbal position, kinematic jointposition, acceleration, velocity, mechanism stiffness, or mechanismprecision at that point. In step 1254 the slope of the part surface ontowhich material is to be deposited is calculated for the path points, ora function for slope is found in the case of continuous or piecewisecontinuous paths.

In step 1256, in a set of repeated decisions for each point or region onthe path, it may be determined if the local path slope is positive,negative, or zero. For each point or region on the path, if the localslope is negative, in step 1258, a correction factor may be calculatedequal to the absolute value of (one half the nozzle tip outer dimension,for example a tip outer diameter or width, times the local part surfaceslope at that point). For each point or region on the path, if the localslope is non-negative, in step 1260, a correction factor may becalculated equal to minus one times the absolute value of (one half thenozzle exit orifice dimension, for example an exit orifice diameter orwidth, times the local part surface slope at that point). Correctionfactors for each point or region may be saved for use in later steps. Ina repeated decision step 1262, it is decided whether correction factorshave been calculated for all points or regions along the path. Ifcorrection factors have not been calculated for all points or regions onthe path, step 1256 and the appropriate choice of steps 1258 or 1260 arerepeated for the next path point or region. If correction factors havebeen calculated for all points or regions along the path, then step 1264calculates a second path by subtracting the saved correction factors foreach point or region along the path from the vertical coordinates ofeach point or region along the path. In an optional step 1266, anoptional third path may be calculated by applying any additional desiredcorrection factors for example additional adjustments to path verticalcoordinates to keep the nozzle lower or closer to the part surface whenthe path has a positive slope in order to enhance adhesion of depositedmaterial to the part surface when the nozzle is travelling uphill, orapplying positive or negative adjustments to vertical path coordinatesin order to enhance or change adhesion, texture, thickness, surfacefinish, fill factor or density of deposited material. In step 1268, theresulting path (the second or third path, whichever was final) may beused to guide the material deposition system which may include guiding anozzle to fabricate a part with more consistent resulting depositedmaterial thickness and better adhesion of deposited material to a partsurface.

FIG. 14A shows the nozzle 1202 depositing material 1204 onto partsurface shape 1210 while moving along a path with negative slope andfollowing a path with slope compensation as described above and in FIGS.12C and 13. An arrow 1274 is included in the figure to show direction ofmotion of nozzle 1202. Because motion of nozzle 1202 shown in FIG. 14Ais downhill (i.e., path with downward slope), deposited materialthickness 1256 is largely determined by proximal point or edge 1244 ofthe tip of nozzle 1202. By following a path adjusted according to slopeas described above, deposited material 1270 is able to match desiredmaterial shape 1212 and deposited material thickness 1272 matches adesired deposited material thickness even though nozzle 1202 is movingon a path with negative slope.

FIG. 14B shows the nozzle 1202 depositing material 1204 onto partsurface shape 1210 while moving along a path with positive slope thathas been slope-corrected according to the algorithms described above andin FIGS. 12C and 13. An arrow 1280 is included in the figure to showdirection of motion of nozzle 1202. By following a path adjustedaccording to slope as described above, deposited material 1282 is ableto match desired material shape 1212 and deposited material thickness1276 matches a desired deposited material thickness even though nozzle1202 is moving on a path with positive slope. Thickness of depositedmaterial 1276 may be largely determined by point or nozzle exit orificeedge 1248. Additionally, the gap 1226 shown in FIG. 12B is not presentin FIG. 14B and deposited material 1282 may have improved adhesion topart surface 1210. A distance 1278 is shown between nozzle 1202 and partsurface 1210. Distance 1278 is desired to be positive, i.e., a gap ispresent, so that nozzle 1202 doesn't scrape or harm part surface 1210.Under certain geometry conditions path adjustments as described aboveand outlined in FIGS. 12C and 13 may result in distance 1278 being lessthan or equal to zero. Under such conditions, additional pathadjustments may be applied to ensure that distance 1278 is greater thanzero.

Referring now to FIGS. 15A-15D, FIG. 15A shows a top view of a desiredpart 1502, and FIG. 15B shows a front view of desired part 1502 (drawnwith hidden lines dashed so that the non-planar shape of the part isvisible), FIG. 15C shows an isometric view of the part 1502 (drawn withhidden lines dashed so that the non-planar shape of the part isvisible), and FIG. 15D shows a part 1504 that is divided into non-planarlayers 1506 on top of a base part 1508. The part 1504 represents amanufactured version of part 1502. The part 1504 is manufactured bydepositing layers of material 1506 sequentially on top of the base part1508. Layers 1506 may have non-uniform thickness, that is they may havea thickness that varies across each layer up to an optional maximumamount and down to an optional minimum amount. The part 1504 may beremoved from the base part 1508 after fabrication of the part 1504 iscomplete. The base part 1508 may be a pre-fabricated part made bymachining or molding or any 3D printing technique. The base part 1508may be made of a material that releases from the material of the part1504 or it may be a dissolvable or meltable material, or there may be anadditional layer of release material (not shown) between the base part1508 and the part 1504. Fabrication of the part 1504 by layers 1506 maybe as follows: a layer 1510 is deposited first on top of the base part1508, followed by a layer 1512, which is followed by a final layer 1514.The local number and thicknesses of layers 1506 may be chosen asfollows: first a maximum layer thickness may be specified, then thelocal thickness of the outer shape of part 1504 may be divided by themaximum layer thickness. If there is no remainder from the divisionoperation (i.e., the local thickness of the part 1504 is an integermultiple of the maximum layer thickness), then the result of thedivision operation may be used as the number of layers. If the remainderis non-zero, then the number of layers can be the result of the divisionoperation plus one (i.e., an extra layer is added so that no layer isover the maximum thickness). In the manufacturing method described here,there may be a minimum thickness, but the layer thickness does not needto be constant across each layer and layers may have differingthicknesses from one another. In a simple case, layers may locally havethe same thickness, and thickness may be determined by dividing thelocal thickness of the part 1504 by the number of layers determined forthat location. The number of layers does not need to be constant acrossthe area of the part 1504. For example, if the part 1502 is to be usedas a shape on which to base the shape of the part 1504, the number oflayers across the span of the part as shown in FIG. 15A does not need tobe constant.

Using conventional FDM techniques, such parts would be fabricated inflat layers of constant thickness which do not represent the shape ofthe part very well. By using non-planar layers and layers ofnon-constant thickness as shown in FIG. 15D, however, the desired partshape 1502 can be better represented in the part 1504. The part 1504 mayalso be manufactured more quickly and be stronger.

FIG. 15E shows layers 1506 as fabricated out of material filaments 1516which have been deposited along non-horizontal and sometimes non-planarpaths so they can follow the form of each layer. Filaments 1516 may bemade by the FDM process. Filaments 1516 may have a constant width asshown in this figure, or they may have variable width. In this case, thedeposition rate (volume of material deposited per linear distance movedby a material deposition device) changes along the filament length as itis created in order to achieve the varying filament thickness needed tomatch the varying thickness of layers 1506 while keeping the widthconstant as shown. Alternatively, the width of the filaments could bevaried while keeping the material deposition rate constant in order toachieve a desired layer thickness. In some cases, both the width andmaterial deposition rate can be varied along the length of the filament.

FIG. 15F shows the part 1504 with layers 1506 exploded so the filamentpatterns 1516 a-c are more clearly visible. Layers 1510 and 1514 havefilaments 1516 a,c arranged in a pattern that runs predominantly acrossthe layer surface. The layer 1512 has filaments 1516 b arranged in apattern that is predominantly aligned with the long direction of thelayer surface. Using filament patterns that cross or are close toorthogonal from one layer to another can create structural advantages.In practice, filaments may be arranged in other arrangements as wellincluding filaments in all layers being aligned or filaments of everylayer going in a different direction or some other arrangement.

FIG. 15G shows an isometric view of a desired part 1518. Part 1518 issimilar to part 1504 of FIGS. 15C-F except that it has a boss 1520 atone end which protrudes vertically from part 1518.

FIG. 15H shows an isometric section view, taken along section line A-Ain FIG. 15G, of the part 1518 as divided into non-planar layers 1522 ontop of a base part 1524.

Referring also to FIG. 15I, an example fabrication of the part 1518 withnon-planar layers 1522 includes depositing material 1528 from a nozzle1526.

FIG. 15J shows a side view of part 1518 with non-horizontal andoptionally non-planar layers 1522 being fabricated by depositingmaterial 1528 from nozzle 1526. Nozzle 1526 has a side angle 1530 whichdetermines the steepest angles of parts or layers or faces that it mayoperate immediately adjacent to or deposit material on. In FIG. 15J, alayer 1532 has an angled shape matching or nearly matching angle 1530 sothat nozzle 1526 may operate immediately adjacent to it without crashinginto it, and further nozzle 1526 may deposit material such as layer 1542on to it including onto its angled face. Part 1518 and layers 1522 maybe constructed with the following algorithm: first an upper spanninglayer 1532 is planned which spans the area or horizontal extents of part1518. Spanning layer 1532 may be non-horizontal or non-planar. A minimumangle from vertical for a layer 1532 is chosen which allows nozzle 1526to operate immediately adjacent at any location above layer 1532. Layer1532 is also designed to match the shape of the upper surface of part1518 as closely as possible while not violating the minimum allowableangle from vertical (or alternately a maximum allowable angle fromhorizontal).

In some areas, the shape of layer 1532 matches the upper surface of part1518 perfectly, and in other areas, layer 1532 must lie below the uppersurface of part 1518 in order to stay at or above the minimum allowableangle. In areas where it does not match the shape of the upper surfaceof part 1518, more material layers such as layer 1542 will need to bedeposited on top of layer 1532 in order to attain the full shape of part1518. The thickness of layer 1532 is chosen as follows: a minimum numberof spanning layers may be chosen (layers which span the area of part1518 as projected on a plane perpendicular to an axis 1544 of nozzle1526 such as layer 1532, layer 1536 and layer 1538), then a maximumlayer thickness may be specified, then in a first division operation thelocal thickness in a direction parallel to axis 1544 of the shape ofpart 1518 may be divided by the maximum layer thickness. If there is noremainder from the first division operation (i.e., the local thicknessof part 1518 is an integer multiple of the maximum layer thickness),then the result of the division operation may be used as the number oflayers. If the remainder of the first division operation is non-zero,then the number of layers can be the result of the first divisionoperation plus one or more layers (i.e., at least one extra layer isadded so that no layer exceeds the maximum thickness).

The number of layers does not need to be constant across part 1518 (forexample across the area of part 1518 as projected on a planeperpendicular to axis 1544). For example, if part 1502 (FIG. 15A) is tobe used as a shape on which to base the shape of part 1518, the numberof layers across the span of the part shown in FIG. 15A does not need tobe constant. After the number of spanning layers and the number of locallayers has been determined for all desired locations across part 1518,the specific local thicknesses and orientations of each layer may beplanned. The number of upper spanning layers may be decided. In FIG.15J, there is one upper spanning layer, layer 1532. The number of lowerspanning layers may be decided. In FIG. 15J, layer 1536 and layer 1538are the lower spanning layers (there are two lower spanning layers inthis example). The shape of the uppermost spanning layer (in this caselayer 1532) may be determined. The shape of the uppermost spanning layermay have an upper boundary which follows the shape of part 1518 whereverfeasible and may deviate from the shape of part 1518 in areas whereangle 1530 would prevent layer 1532 from being fabricated. Put anotherway, uppermost layer 1532 follows the shape of part 1532 everywhereexcept where its slope would be less than angle 1530 from vertical. Alower boundary of layer 1532 may be determined by offsetting inward fromthe upper boundary of layer 1532 by an amount equal to the desired locallayer thickness at each local location. Shape and thickness informationfor layers may be continuous or it may be represented as data points atdiscrete locations.

In areas where the shape of part 1518 is less than the slope of angle1530 from vertical, the upper boundary of uppermost layer 1532 may beshaped so that it is equal to or greater than angle 1530 from verticalso that nozzle 1526 may later traverse adjacent to layer 1532 anddeposit additional material in those areas in the form of additionallayers such as layer 1542. Layer 1532 may have a ledge 1540 in an areawhere the local thickness of layer 1532 may be locally increased withoutinhibiting motion of nozzle 1526 as it may deposit additional subsequentlayers such as layer 1542. Once the shape of the uppermost spanninglayer is determined, the shapes of any remaining upper spanning layersare determined. The shape of the upper boundary of next inwardadditional upper spanning layer (if it exists) may be the shape of thelower boundary of the layer lying immediately above (in this case layer1532). The shape of a lower boundary of a next upper spanning layer maybe determined by offsetting downward from the upper boundary of thelayer by an amount equal to the local thickness for that layer. Theshape of additional upper spanning layers may be similarly determined byoffsetting the shape of the layer above downward by the desired localthickness of the layer whose shape is being determined. In this example,there are no additional upper spanning layers. The shape of thelowermost spanning layer 1538 may be determined by matching the lowerboundary of the shape of part 1518 and adjusting the upper boundary oflayer 1538 according to the determined local thickness for layer 1538.Layer 1538 may have the maximum layer thickness in some locations wherethat does not cause other layers to fall below a minimum thicknessvalue. The shape of a next lower spanning layer 1536 is determined byusing the upper boundary of layer 1538 as a lower boundary of layer1536. An upper boundary of layer 1536 may be determined by offsettingthe lower boundary of layer 1536 by the desired local thickness forlayer 1536.

In some cases, the local thicknesses of the spanning layers may bedetermined. In the example shown in FIG. 15J, upper spanning layer 1532was chosen to have the maximum layer thickness at all locations wherethere are locally more total layers than spanning layers.

In some cases internal fill layers may be used in some areas if a solidpart is desired. Layer 1534 is an example of an internal fill layer.Layer 1534 may not span the area of part 1518. The thickness of internalfill layers may be determined by a third division operation in which theremaining unfilled thickness between upper spanning layer 1532 and lowerspanning layer 1536 is divided by the maximum layer thickness or by adesired layer thickness. If the remainder of the third divisionoperation is zero (i.e., the desired thickness used divides theremaining thickness evenly), then the result of the third divisionoperation may be used as the local number of internal fill layers. Ifthe remainder of the third division operation is not zero, then one ormore layers may be added so that no layer exceeds the maximum or desiredthickness value. Internal fill layers such as layer 1532 may be formedin any shape including non-flat, non-horizontal or non-planar shapes.Alternatively, they may be formed to be planar. A combination of planarfill layers and non-planar spanning layers may be used to increase partstrength and eliminate any planar layer interfaces across any part crosssection in any area. Internal fill layers may be added prior to upperspanning layers.

In some cases external fill layers may be used in some areas to achieveexternal part shapes with an angle less than the nozzle angle asmeasured from vertical such as angle 1530 of FIG. 15J (or greater thanthe side angle of the nozzle measured from horizontal). Referring alsoto FIG. 15H, layers 1550, 1542, 1546 and 1548 are external fill layersthat may be added subsequent to upper spanning layers such as upperspanning layer 1532. External fill layers may be non-planar ornon-horizontal or they may be horizontal. In this example they are shownto be horizontal and planar except for areas which interface withnon-planar spanning layers below them. For example, layer 1550 has alower boundary that is non-planar and follows the non-planar shape ofspanning layer 1532 which lies below it. External fill layers may beadded lowest layer first (such as layer 1550 or in some locations 1542),followed by next lowest and so on until an uppermost external fill layeris added, in this case layer 1548. External fill layers may havethickness that varies across the area of each layer.

While FIG. 15J shows layer thicknesses in a single direction, the numberof layers and layer thicknesses may vary in any direction across thearea of part 1518. In the layer planning method and manufacturing methoddescribed above, there may be a minimum thickness, but the layerthickness does not need to be constant across each layer and layers mayhave differing thicknesses from one another. In a simple case, layersmay locally have the same thickness, and thickness may be determined bya second division operation in which the local thickness of part 1518 isdivided by the number of layers determined for that location.

All layers including spanning layers, internal fill layers and externalfill layers may be fabricated deposition of material. Material may bedeposited via a nozzle in a pattern that closely approximates thedesired shape of each layer.

Referring now to FIG. 16A, a front view of one implementation of aconnector member 1602 is shown. The connector member 1602 may have aportion 1604 that matches the shape of a surrounding material layer (notshown) and it may have a portion 1606 which protrudes in a differentdirection. Portion 1606 may protrude normal to a surrounding materiallayer, or it may protrude at some other angle. Connector member 1602 maybe formed by a material deposition system such as nozzle 1608. Thenozzle 1608 may follow a path which causes it to deposit portion 1604first and thereby adhere portion 1604 to the surrounding material beforechanging direction of motion and forming portion 1606 which may protrudefrom surrounding material. A curved arrow is shown to represent thedirection and path of motion that nozzle 1608 may follow. Connectormember(s) such as 1602 may be used to interconnect or form a mechanicaljoining of material layers or material structures such as those producedby fused deposition modeling and other forms of 3D printing includingmaterial deposition, material solidification, SLA, SLS, DMLS, andmaterial jet techniques such as Objet.

Referring also to FIG. 16B, the connector member 1602 with an optionalauxiliary member 1610 is shown. Member 1610 may match the shape of asurrounding material layer and may be joined to member 1602 at amaterial junction 1612. Member 1610 may be formed or deposited prior tothe forming of member 1602 so that as member 1602 is formed, it may beformed so that it touches member 1610 at junction 1612. Members 1602 and1610 may be formed of polymer materials, and they may be hot whendeposited (above a glass transition temperature or above a liquidustemperature) so that member 1602 may adhere to member 1610 at junction1612. Members may also be formed of other materials such as wax, metal,carbon fiber composites, fiberglass composites, thermoset resins, woodcomposites, ceramic composites, or combinations thereof.

FIG. 16C shows a structure 1614 having multiple connector members 1602.Members 1602 may be formed sequentially starting with a lowest member1616 and ending with an uppermost member 1618. Members 1602 may form abond or adhesion at common boundaries between them when a member 1602 isformed on top of another member 1602. Each member 1602 may have aprotruding region 1606. As the protruding region 1606 of each member1602 is formed, the region 1606 may bond to or be mixed with or beinterlinked with the region 1606 of the member 1602 that it is beingformed on top of (i.e., the “prior member”). The protruding region 1606of the prior member may be somewhat deformed by the nozzle 1608 as thenext protruding region 1606 is being formed. Such deformation may betolerable as long as regions 1606 become bonded, welded, or interlinked.The net result of combining multiple members 1602 and protruding regions1606 may be that a region of continuous transverse bonding 1620 may beformed which may have a direction of structural integrity which isdifferent than or orthogonal to the predominant material depositiondirection of material regions 1604 and therefore be in a directiondifferent than or orthogonal to the predominant material direction ofmembers 1602 and structure 1614. In this way, the structure 1614 can becreated which has strength across layers and has strength not only in apredominant material direction or plane, but also has strength in adirection transverse to the predominant material direction or plane.

FIG. 16D shows another implementation of a transverse connectedstructure 1622 having connector members 1602. This structure is similarto structure 1614 of FIG. 16C except that in structure 1622, members1602 have varying orientations. Protruding regions 1606 of members 1602may be bonded, welded, or interlinked to form a region of transversebonding 1620 as part of structure 1622, similar to region 1620 ofstructure 1614. Structure 1622 may be used alone or may be part of alarger or more solidly packed structure and may serve to providestrength transverse to a predominate material or structure direction orplane.

FIG. 16E shows a structure 1624 which incorporates many connectormembers 1602 and multiple transverse connected structures 1622. Onestructure 1622 is shown in cross section so the bonding or interlinkingof the material of the multiple members 1602 is visible in aninterlinking region 1626. Structure 1624 is shown partially populatedwith members 1628 which include the members 1602 which make upstructures 1622. Members 1628 may also include additional members whichare horizontal or other members which are not horizontal but do not havetransverse regions like members 1602. While structure 1624 is shownsparsely populated for clarity in FIG. 16E, it is also possible toconstruct similar structures that are more solid, that is where allavailable spaces are occupied by members so that the structure behavessimilarly to a solid or semi-solid material. The incorporation oftransverse connected structures within structure 1624 can createtransverse strength so that structure 1624 may have greater strength ina transverse direction than typical FDM structures which do notincorporate transverse connected structures. All members may have somedegree of bonding, welding, or interlinking where they cross othermembers. Members may be of the same material or they may be of differentmaterials so that different bulk properties may be created in differentareas or in different directions. While transverse connected structures1622 are shown protruding through the top of structure 1624 in FIG. 16E,the protruding elements of structures 1622 may be terminated at anydesired level and smooth material or members or layers may be depositedover the top of structures 1622 which may enable structures similar to1624 to have smooth or uniform surfaces.

FIG. 16F shows a larger structure 1630 which incorporates multipletransverse connected structures 1622 and connector members 1602 (seeFIGS. 16A-D). Structure 1630 is similar to structure 1624, but shows howa larger structure can be constructed that incorporates transverseconnected structures 1622 based on similar principles.

FIG. 16G shows a structure 1632 having a connector member 1602.Structure 1632 has one layer of members 1634 which are aligned in apredominant direction. Connector member 1602 forms part of layer 1634and may be bonded, welded, or interlinked with adjacent members asadjacent members are formed.

FIG. 16H shows a structure 1636 having a connector member 1602.Structure 1636 is the same as structure 1634 but further includes asecond layer of members 1638. The members of layer 1638 may be orientedin a direction different than or orthogonal to those of layer 1634.Members of layer 1638 may bond to members of layer 1634, but nominalinter-layer strength may not be as high as desired due to the nature ofthe bond.

Referring further to FIGS. 16I and 16J, the structure 1636 is shown withthe connector member 1602 reformed and bent over. Member 1602 may bereformed and bent over by a material deposition nozzle, for example.

Referring further to FIGS. 16K and 16L, a structure 1640 includes thestructure 1636 but adds a third layer of members 1642 on top of thesecond layer of members 1638. As members of layer 1642 are formed, theymay bond, weld, or interlink with the bent portion of member 1602. Themember 1602 may become effectively fused with layer 1642 as a result.That is, the connector member 1602 may become a continuous materialconnection between member layers 1634, 1638, and 1642. This type ofinter-layer connection can add trans-layer strength to structures suchas structure 1640 which may be lacking in layered structures typicallycreated by conventional FDM processes. FIG. 16L shows a front view ofthe structure 1640. The deformed connector member 1602 is shown indashed lines so that its shape and connection with layers 1634, 1638,and 1642 is more clearly visible.

Referring now to FIG. 17A, one implementation of a connector member 1702is shown. The connector member 1702 may have regions 1704 which matchthe shape of surrounding material (not shown). Regions 1704 may beplanar or horizontal, or they may follow a non-planar shape. Surroundingmaterial (not shown) may be in the form of planar or non-planar layersand regions 1704 may make up part of the shape of the planar ornon-planar layers. Connector member 1702 may have a protruding region1706 which may protrude from or differ from the shape of any surroundingmaterial or from the shape of regions 1704. The protruding region 1706may protrude in an upward direction, a downward direction, or in adirection transverse to a predominant shape of regions 1704. Protrudingregion 1706 may be used to interlink connector member 1702 with othermembers, layers or regions in a structure (not shown in this figure).

FIG. 17B shows a structure 1708, which includes the connector member1702. A material deposition nozzle 1710 is shown depositing material tocreate an interlinking member 1712. Interlinking member 1712 may beformed by material deposition nozzle 1710 with material being depositedat a typical rate until nozzle 1710 comes close to member 1702 andprotruding region 1706, at which time nozzle 1710 may deposit additionalmaterial to form an enlarged region 1714. By depositing additionalmaterial in proximity to protruding region 1706, enlarged region 1714may grow and increase in size until it flows underneath protrudingregion 1706. Enlarged region 1714 may also bond, weld, fuse, orinterlink with material from member 1702 and the protruding region 1706.

Referring further to FIG. 17C, a structure 1716 adds an additionalinterlinking member 1718 to the structure 1708. Interlinking member 1718may be formed in the same manner as interlinking member 1712.Interlinking member 1718 may have an enlarged region 1720. When theenlarged region 1720 is formed, it may flow under protruding region 1706of connector member 1702. The material of enlarged region 1720 may bond,fuse, weld, or interlink with material from enlarged region 1714 ofinterlinking member 1712 and with protruding region 1706 of connectormember 1702. While additional members are not shown in this figure forclarity, in practice, interlinking members 1712 and 1718 may be formedon a layer in a different plane than connector member 1702. Thefabrication of structure 1716 therefore represents a method of creatinga strong bond, weld, interconnection, or interlinking of members andmaterial layers on different planes that is stronger than typical weakinter-layer bonds created in structures made via conventional FDMtechniques. Non-planar material members or layers may be similarlyinterlinked with connector members and interlinking members orcombinations thereof creating structural links between adjacentnon-planar layers.

FIG. 17D shows a structure 1722, which includes the structure 1716 butadds additional members that make up a lower layer 1724 and an upperlayer 1726. Upper layer 1726 includes additional interlinking members1728 which have been formed so that they bond or fuse with protrudingregion 1706. Structure 1722 represents a structure in which materialmembers or layers on different planes may be structurally interlinked ina way that is stronger than typical weak inter-layer bonds created byconventional FDM techniques.

FIG. 18A shows another implementation in the form of a connector member1802. Connector member 1802 includes a protruding loop 1804. Theprotruding loop 1804 may protrude out of the plane of a surroundingmaterial layer (not shown). Protruding loop may protrude upward ordownward or in a direction transverse to connector member 1802.

FIG. 18B shows an isometric view of a structure 1806, which includes theconnector member 1802. A material deposition nozzle 1808 is showndepositing material to form an interlinking member 1810. The nozzle 1808may deposit additional material in proximity to protruding region 1804of connector member 1802 to form an enlarged region 1812. The materialof enlarged region 1812 may bond, weld, fuse, or interlink with theprotruding region 1804 and the member 1802. The member 1810 may lie in adifferent plane than the member 1802 if the members are planar. Ifmembers 1802 and 1810 are non-planar, they may lie adjacent to eachanother.

FIG. 18C shows a structure 1814, which the structure 1806 of FIG. 18Bbut adds an additional interlinking member 1816. The interlinking member1816 may have an enlarged region 1818, similar to the enlarged region1812 of interlinking member 1810. The material of enlarged region 1818may form a bond, weld, fusion, or interlinking with adjacent material ofother members including interlinking member 1810 and protruding loop1804 of connector member 1802.

FIG. 18 d shows a structure 1820, which includes the structure 1814 butadds additional members that have been formed to create a lower layer1822 and an upper layer 1824. To create structure 1820, it may benecessary to form all members of lower layer 1822 before forming membersof upper layer 1824. Additional interlinking members 1826 have beenadded as part of upper layer 1824. Interlinking members 1826 may bond,weld, fuse, or interlink with protruding loop 1804 and connector member1802 as well as other adjacent members. Structure 1820 illustrates how astructure may be created that has structural interlinking between layersthat is stronger than the typically weak inter-layer bonds that areformed in structures made via conventional FDM processes.

Referring now to FIG. 19A, a partially completed structure 1902 that isbeing formed by a material deposition system 1906 is shown. Thestructure 1902 may include non-planar material layers 1904. The materialdeposition system 1906, cross sectioned for clarity, is shown depositingmaterial 1908 onto structure 1902. The material deposition system 1906may be a nozzle. The material deposition system 1906 may have a sideangle 1910, which is shown here measured with respect to vertical.Structure 1902 and layers 1904 are shown having an “egg-crate”-like formwith protrusions 1914 and valleys 1916. The form of protrusions 1914 andvalleys 1916 may have a limit angle 1912 which may be the minimumallowed angle as measured from vertical. Angle 1912 may be a determiningfactor of the form of layers 1904, protrusions 1914, and valleys 1916.Angle 1912 may be chosen to be as small as possible while not being lessthan angle 1910, or it may be chosen to be angle 1910 plus anincremental safety factor. By choosing angle 1912 to not be less thanangle 1910, material deposition system 1906 mal be able to access anentire working upper surface 1918 of structure 1902. Working uppersurface 1918 may be the exposed upper surface of whatever layer 1904 orcombination of layers 1904 are exposed at a given time during thefabrication process of structure 1902. By choosing a form for layers1904 with protrusions 1914 and valleys 1916 and angle 1912 as small aspossible, bondable surface area of layers 1904 may be at or near amaximum achievable bondable surface area while still being accessibleand fabricatable by material deposition system 1906. Additionally, aform as described with minimum angles 1912 may have no planes ofcleavage between layers 1904. Both maximized bondable area betweenlayers and elimination of cleavage planes between layers may allowstructure 1902 to have higher inter-layer strength and greaterresistance to delamination and improved structural properties ascompared to structures fabricated via conventional material depositiontechniques such as FDM with planar, horizontal layers.

FIG. 19B shows a structure 1903, which adds additional layers 1904 tothe structure 1902 including partial layers 1920 which may combine toform a flat upper surface 1919, which may alternatively take any desiredshape. Structure 1903 depicts how non-planar layers 1904 plus partiallayers 1920 can be used to form a structure with planar faces,non-planar faces, or any desired shape. Desired shapes with areas withslope angles less than angle 1910 of FIG. 19A may be formed with acombination of non-planar layers such as layers 1904 plus externalplanar layers as shown in FIGS. 15A-15J.

FIG. 19C shows a front view of a structure 1922 having layers 1924.Structure 1922 is similar to structure 1903 of FIG. 19B except thatlayers 1924 have shapes chosen such that each layer 1924 has a constantthickness. A limiting layer 1926 may be included which has a shapedesigned according to minimal angle 1912 as in FIG. 19A. To keep layerthickness constant, the shapes of other layers 1924 are offset shapesfrom layer 1926 and therefore may have angles greater than angle 1912over a larger portion of their extents. An optional bottom layer 1928and an optional top layer 1930 are shown that have non-constantthickness. Layers 1928 and 1930 may be used to create smooth or planaror non-planar top and bottom surfaces.

FIG. 19D shows a front view of a structure 1932 with layers 1934.Structure 1932 is similar to structure 1903 of FIG. 19B except thatlayers 1934 have shapes chosen such that the shape of each layer may bethe same (except where they are incomplete to allow for top and bottomstructure surfaces). Layers 1934 may have varying thickness in order toachieve the same shape for each layer 1934. Using layer shapes that arethe same and are “stackable” may allow for smaller angles 1912 overgreater extents of structure 1932 which may allow for bondable surfacearea to be maximized and may allow for the greatest deviation fromplanar layer shapes which may increase structure strength. Structure1932 includes an optional bottom layer 1936 and an optional top layer1938. Layer 1936 and 1938 may be planar layers and may have constantthickness and may serve to create smooth or aesthetic top and bottomsurfaces.

FIG. 20A shows an example of a system 2002 for fabricating 3D objectswith continuously variable colors, material properties, or a combinationthereof. System 2002 may include a material combining system 2004, amaterial combining system controller 2024, a material shaping system2006, a material sizing system 2008, a material buffer or storage system2010 and a material deposition system 2012. Material combining system2004 may serve to combine materials 2014, which may be of differingtypes, colors, shapes or material properties, into a combined material2016. Material combining system 2004 is shown cross sectioned in FIG.20B to reveal the flow of materials through it.

Material shaping system 2006 may serve to change or enforce or solidifythe shape of combined material 2016 to yield shaped material 2018.Material sizing system 2008 may serve to adjust the size of shapedmaterial 2018 and may optionally or selectively remove a portion ofmaterial 2018 to yield sized material 2020. Material shaping system 2006or material sizing system 2008 or some other system may add optionaldrive or syncing features 2022 to shaped material 2018 or to sizedmaterial 2020. A small number or coverage of syncing features 2022 areshown for clarity, but in practice syncing features 2022 may be placedall along the length of shaped material 2018 or sized material 2020 orthey may be placed at regular intervals or at irregular intervals.

If syncing features are placed at irregular intervals, they may serve asmarkers which may be read or synced to by material deposition system2012. If syncing features 2022 are added to shaped material 2018, theymay persist as part of sized material 2020. Sized material 2020 may bestored for future use on a spool or in a container, or it may be feddirectly to material deposition system 2012, or it may have a serviceloop, storage system or other buffer such as buffer 2010. Buffer 2010may serve to allow system 2002 to operate with a different feedrate orintermittent feed for material deposition system 2012 as compared to thefeedrate of material combining system 2004.

Materials 2014 may be controllably fed into material combining system2004 at different rates to create any desired combined ratio of theindividual input materials. If input materials 2014 have differentcolors or material properties, combined material may therefore have anymixture of those properties or colors, and the mixture of colors ormaterial properties or the ratio of materials may be varied continuouslyalong the length of combined material 2016. Input materials 2014 may beany material including polymer filaments such as those used forconventional FDM 3D printing systems. Combining system 2004 is shownreceiving 5 input materials 2014 in FIG. 20A, but nearly any number ofinput materials is possible.

For mixing of colors, input materials 2014 may be red, green and blue,or they may be cyan, yellow, magenta, black and white, or they mayinclude purple, blue, green, yellow, orange, and red, or translucent,fluorescent, metallic, pearlescent colors or any combination thereof.For achieving material 2016 with variable material composition orproperties, input materials 2014 may include polymers, waxes,elastomers, rubbers, mineral fillers, metals, metal-polymer composites,carbon-fiber, carbon fiber composites, Kevlar, spectra, nylon, ABS(Acrylonitrile Butadiene Styrene), PLA (Polylactic acid), PET(Polyethylene terephthalate), PC (Polycarbonate), PVA (Polyvinylalcohol), polystyrene, dissolvable materials, meltable materials,fibers, particulate composites, wood-based materials, or combinationsthereof. Combined material 2016 may be suitable for use as an inputmaterial for conventional, existing or new FDM systems. Shaped material2018 and sized material 2020 may also optionally be used as inputmaterial for other FDM systems as well as being used as input formaterial deposition system 2012.

Material deposition system 2012 may include feed drive 2026 and nozzle2028. Feed drive 2026 may sync with syncing features 2022. Feed drive2026 may sync with syncing features 2022 by mechanical fit, or byintelligent control by controller 2024 or some other controller.Controller 2025 may communicate and control the actions of combiningsystem 2004 and material deposition system 2012 via communication links2025. Controller 2024 may also communicate with and control shapingsystem 2006 or sizing system 2008 or combinations thereof for example toenable closed-loop control of shaping or sizing or creation of syncingfeatures 2022.

By creating syncing features 2022 in close proximity to the materialcombining function of material combining system 2004, syncing features2022 may allow the syncing of feed drive 2026 with syncing features 2022on material 2020 and therefore maintaining sync between materialdeposition system 2012 and the instantaneous or localized materialcomposition, properties or color of material 2020. Controller 2024 maycontrol the feedrates of systems 2004 and 2006 and 2012 and may controlthe syncing, or the syncing may be maintained by purely mechanical oropen-loop methods or actions. In this way parts may be created bymaterial deposition system 2012 in full color or variable materialcomposition with low error (<1 mm material length) between aninstantaneously specified material color or composition to be depositedand the actual position of the corresponding material color orcomposition on material 2020, as material 2020 is being fed throughnozzle 2028 and deposited on a part.

Syncing features 2022 may act like ridges on a timing belt so thatmaterial deposition system does not accumulate errors in the position ofmaterial 2020 over time beyond a possible very small non-accumulatingerror that may be due to clearance between syncing features 2022 andcorresponding syncing features on material drive system 2026. Materialdrive system 2026 is shown as wheels with optional syncing features, butit may also include, belts, gears, smooth rollers, reciprocating feeddogs or vibrating feed components or combinations thereof.

Another optional way of syncing the locations of material ratio orcomposition of material 2020 with feed drive 2026 is the use of markers2030 which may be placed into or on material 2020 by systems 2004, 2006or 2008 at specified locations corresponding to changes in materialratio or color or at other desired points. Markers 2030 may be physicalfeatures such as notches, holes, grooves or bosses, or they may bechanges in the material composition or ratio. For example, one of inputmaterials 2014 may be a marker material such as a material that reflectsor absorbs ultraviolet (UV) light or fluoresces under UV light or someother frequency of light or it may be a different material that may bedetectable by deposition system 2012 or controller 2024, but may not bereadily visually detectable by humans.

Optional syncing features 2022 may have shapes such that an area of thecross section of material 2020 is constant along the length of material2020. A constant material cross section for material 2020 may enable amore easily controllable or continuous feedrate of material through andout of nozzle 2028. A variety of shapes for syncing features 2022 arepossible such that the cross sectional area of material 2020 will remainconstant including offset bosses, indentations, notches, grooves, bars,spiral ridges, threads or grooves and chevron features. FIG. 20A showsone version of offset chevron shapes for syncing features 2022. Material2020 may be fed through nozzle 2028 where it may be extruded with orwithout heat and deposited on a part surface (not shown). Nozzle 2028 isshown cross sectioned to reveal the passage of material 2020 through it.

FIG. 20B shows a schematic front cross section view of materialcombining system 2004 and material shaping system 2006. System 2004 mayinclude input material feed systems 2032, which may controllably feedinput materials into a combining chamber 2036. Feed systems 2032 areshown as feed rollers, but they may include belts, gears, reciprocatingfeed dogs, vibrating feed components or combinations thereof. Inputmaterials 2014 may pass through restriction orifices 2034 which mayserve to prevent backflow and mixing of input materials 2014 before theyhave entered mixing chamber 2036. Mixing chamber 2036 may include mixingvanes, grooves, or members to promote convoluted flow and mixing (notshown). Mixing chamber 2036 may include valves or flow preventers (notshown). Mixing chamber 2036 may include an exit orifice 2038 that mayhave a diameter or width smaller than mixing chamber 2036. Mixingchamber 2036 may be heated to melt or activate input materials.

Input materials 2014 may be insulated from heat from mixing chamber 2036or they may be actively cooled until they reach restriction orifices2034 where they may become softened or liquefied before or as they entermixing chamber 2036. Material feed systems 2032 may be controlled bycontroller 2024 such that they feed their respective input materials2014 at predetermined rates corresponding to a desired material or colorratio of combined material 2016. FIG. 20B shows combined material 2016being shaped by material shaping system 2006. Material shaping system2006 may include shaping rollers 2040. Combined material 2016 may be hotor soft enough to change shape as it passes between rollers 2040.Material shaping rollers 2040 may create syncing features 2022 in shapedmaterial 2018 by embossing, squeezing, indenting, turning, or shiftingmaterial 2018. The rate of shaping system 2006 may controlled bycontroller 2024 to match the rate of combining system 2004.

FIG. 20C shows an isometric view of material combining system 2004,material shaping system 2006, and material sizing system 2008. Materialsizing system 2008 may include a blade, a set of pinch rollers or shearrollers, a reciprocating shear, a laser or water jet cutter, or it mayinclude a rotary cutter 2042. Shaping rollers 2040 may provide a primarycross section area through which material 2016 passes and may have a gapon one side which may allow a fraction of material 2016 which may be inexcess of the primary cross section area to flow or escape and form athin discard flange 2044 on one side of shaped material 2018. Materialsizing system 2008 may remove discard flange 2044 or other excessmaterial from material 2018, yielding sized material 2020 which may havea more precisely controlled remaining cross section area than combinedmaterial 2016 or shaped material 2018. For example, material 2020 mayhave a standard deviation of cross section area less than 1% of theaverage cross section area for a batch of material, whereas typical FDMmaterial that has not been processed by additional shaping and sizingsystems may have a standard deviation of cross section area greater than2% of the average cross section area of a batch of material.

In system 2002, shaping system 2004, sizing system 2006 and syncingfeatures 2022 are optional. It is also possible to produce combinedmaterial 2016 with continuously variable color or composition with crosssections that may be round, square, rectangular, triangular, hexagonal,corrugated, oval, tubular or combinations thereof. Combined material2016 with a round cross section and variable color or composition may beused directly in many existing FDM systems.

If syncing features 2022 are created for a batch of material 2018 ormaterial 2020, a corresponding dataset or data file may be created thattells a controller (possibly on a different FDM system) how to syncmaterial 2018 with volumetric or surface locations in a correspondingpart. FIG. 20D shows a flow chart of an example of a process that can beused with one or more of the systems of FIGS. 20A-20C. At 2062, a feedrate for each of at least two different input materials is independentlycontrolled. For example, as noted above, the controller 2024 can controlfeedrates of material combining system 2004 to generate a processedmaterial that varies in composition along its length. In someimplementations, the different input materials are different FDMfilaments.

At 2064, syncing features are added to the processed material. Forexample, as noted above, the controller 2024 can control the materialshaping system 2006 to enable closed-loop control of creation and use ofsyncing features 2022. In some cases, the controller 2024 also controlsthe sizing system 2008, as noted above. In any case, the syncingfeatures can be useable by a 3D printer to synchronize the variation incomposition of the processed material during 3D printing of an objectusing the processed material.

In some implementations, at 2066, a check is made as to whether theprocessed material will be used locally. Note that some implementationscreate and use the processed material all within the same system, someimplementations create the processed material for use in a separateadditive manufacturing system, and some implementations create theprocessed material for either use in additive manufacturing locally orfor use elsewhere.

For local consumption of the processed material, data can be created at2068, which data is usable by a local 3D printer to sync the processedmaterial with volumetric or surface locations of the object during the3D printing. For example, as noted above, the controller 2024 can alsocontrol the material deposition system 2012, and so the data can becreated for use by the same controller 2024 in charge of both materialpreparation and 3D printing. At 2070, the 3D printer can be controlledto use the processed material, including the synching features, based onthe generated data. In addition, the process can be ongoing, and thecontrolling and adding at 2062 and 2064 can include creating lengths ofthe processed material with continuously variable composition ratios andwith the syncing features placed in specific locations along theprocessed material, the specific locations being coordinated with thecomposition ratios.

In some implementations, the data generated for such processed materialcan be sent to another system for use with this processed material. Forexample, at 2072 a data file can be created in which the data file isusable by an entirely different 3D printer (e.g., an FDM system that isseparate and distinct from an FDM system that creates the processedmaterial). At 2074, this data file can be sent to the different system(e.g., by communication over a wireless network or by communicationthrough a wired computer network) for use with the processed material.

Material 2016, 2018 or 2020 may include discard regions which may serveas a buffer and may allow FDM systems to discard some material if neededor create extra solid infill or interior or exterior part density ifdesired. Material 2016, 2018 or 2020 may include starting and endingregions which may serve to enable loading or feeding of the materialinto feed systems and finishing a print or fabrication session withmaterial still fully engaged in feed systems. Starting, ending anddiscard regions may be fed through an FDM system in a discard area andthe resulting discarded material may be recycled or reused.

The systems shown in FIGS. 20A-20C, such as system 2002, may allow for astand-alone system that may take as input 3D part models with color ormaterial information associated with each volumetric or surface locationin the 3D part models and may produce as output three dimensionalobjects with continuously or discretely variable color or materialcomposition or properties over the surfaces or volumes of the parts thatmay match the input volumetric or surface color or material information.Components of system 2002 may also be retrofitted to existing FDMmachines to enable existing FDM machines to achieve new capabilitiesincluding full color and continuously or discretely variable materialdeposition capability. Components of system 2002 may also be used tocreate batches of material 2020 that correspond to specific parts to befabricated and these part-specific batches of material 2020 may bestored for later use or sold or distributed for use to print thecorresponding full color or variable material parts on different FDMsystems, even though other FDM systems may not have the local capabilityto create combined, shaped or sized variable composition material suchas material 2020.

Implementations of the subject matter described in this specificationcan be implemented in combination with digital electronic circuitry, orcomputer software, firmware, or hardware. Implementations of the subjectmatter described in this specification can be implemented in an additivemanufacturing system that uses one or more modules of computer programinstructions encoded on a computer-readable medium for execution by, orto control the operation of, data processing apparatus. Thecomputer-readable medium can be a manufactured product, such as harddrive in a computer system or an optical disc sold through retailchannels, or an embedded system. The computer-readable medium can beacquired separately and later encoded with the one or more modules ofcomputer program instructions, such as by delivery of the one or moremodules of computer program instructions over a wired or wirelessnetwork. The computer-readable medium can be a machine-readable storagedevice, a machine-readable storage substrate, a memory device, or acombination of one or more of them.

The term “data processing apparatus” encompasses all apparatus, devices,and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, a runtime environment, or acombination of one or more of them. In addition, the apparatus canemploy various different computing model infrastructures, such as webservices, distributed computing and grid computing infrastructures.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, declarative orprocedural languages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, or other unitsuitable for use in a computing environment. A computer program does notnecessarily correspond to a file in a file system. A program can bestored in a portion of a file that holds other programs or data (e.g.,one or more scripts stored in a markup language document), in a singlefile dedicated to the program in question, or in multiple coordinatedfiles (e.g., files that store one or more modules, sub-programs, orportions of code). A computer program can be deployed to be executed onone computer or on multiple computers that are located at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto-optical disks, or optical disks. However, a computerneed not have such devices. Moreover, a computer can be embedded inanother device, e.g., a mobile telephone, a personal digital assistant(PDA), a mobile audio or video player, a game console, a GlobalPositioning System (GPS) receiver, or a portable storage device (e.g., auniversal serial bus (USB) flash drive), to name just a few. Devicessuitable for storing computer program instructions and data include allforms of non-volatile memory, media and memory devices, including by wayof example semiconductor memory devices, e.g., EPROM, EEPROM, and flashmemory devices; magnetic disks, e.g., internal hard disks or removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,special purpose logic circuitry.

To provide for interaction with a user, implementations of the subjectmatter described in this specification can be implemented using acomputer having a display device, e.g., a CRT (cathode ray tube) or LCD(liquid crystal display) monitor, for displaying information to the userand a keyboard and a pointing device, e.g., a mouse or a trackball, bywhich the user can provide input to the computer. Other kinds of devicescan be used to provide for interaction with a user as well; for example,feedback provided to the user can be any form of sensory feedback, e.g.,visual feedback, auditory feedback, or tactile feedback; and input fromthe user can be received in any form, including acoustic, speech, ortactile input.

Implementations of the subject matter described in this specificationcan be implemented using a computing system that includes a back-endcomponent, e.g., as a data server, or that includes a middlewarecomponent, e.g., an application server, or that includes a front-endcomponent, e.g., a client computer having a graphical user interface ora Web browser through which a user can interact with an implementationof the subject matter described is this specification, or anycombination of one or more such back-end, middleware, or front-endcomponents. The components of the system can be interconnected by anyform or medium of digital data communication, e.g., a communicationnetwork. Examples of communication networks include a local area network(“LAN”) and a wide area network (“WAN”), an inter-network (e.g., theInternet), and peer-to-peer networks (e.g., ad hoc peer-to-peernetworks).

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While this specification contains many implementation details, theseshould not be construed as limitations on the scope of the invention orof what may be claimed, but rather as descriptions of features specificto particular implementations of the invention. Certain features thatare described in this specification in the context of separateimplementations can also be implemented in combination in a singleimplementation. Conversely, various features that are described in thecontext of a single implementation can also be implemented in multipleimplementations separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described program components and systemscan generally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular implementations of the invention have been described.Other implementations are within the scope of the following claims.

What is claimed is:
 1. A system comprising: a first system configuredand arranged to combine at least two different input materials; acontroller coupled with the first system and configured to independentlycontrol a feed rate for each of the different input materials into thefirst system to generate a processed material that varies in compositionalong its length; and a second system configured and arranged to addsyncing features to the processed material, wherein the syncing featuresare useable by a material deposition system to synchronize the variationin composition of the processed material during additive manufacturingof an object using the processed material.
 2. The system of claim 1,wherein the different input materials comprise at least three filamentshaving at least three respective different colors, the controller iscapable of continuously varying an amount of each of the at least threedifferent colored filaments, and the first system comprises: an inputmaterial feed system for the at least three different colored filaments;and a mixing chamber having adjacent restriction orifices where thefilaments enter the mixing chamber, and the mixing chamber having anexit orifice with a width that is smaller than the mixing chamber. 3.The system of claim 2, wherein the syncing features comprise markersplaced into or on the processed material at controlled locations.
 4. Thesystem of claim 1, wherein the controller is configured to create datausable by the material deposition system to sync the processed materialwith volumetric or surface locations of the object during the additivemanufacturing.
 5. The system of claim 4, wherein the material depositionsystem is a different fused deposition modeling (FDM) system, and thecontroller is configured to create the data in a data file usable by thedifferent FDM system.
 6. The system of claim 1, wherein the secondsystem comprises a material shaping system, and the syncing featurescomprise shapes added to the processed material.
 7. The system of claim6, wherein the shapes mechanically fit with a feed drive of the materialdeposition system.
 8. The system of claim 7, wherein a cross sectionarea of the processed material in a region of the shapes is constant. 9.The system of claim 8, wherein the shapes are offset chevron shapes. 10.The system of claim 1, further comprising the material depositionsystem.
 11. The system of claim 10, wherein the controller is alsocoupled with and controls the material deposition system.
 12. The systemof claim 10, further comprising a buffer for the processed material,wherein the second system has a controllable feed rate that iscoordinated with the input material feed rates, and the materialdeposition system has a feed rate that is different than the feed rateof the second system.
 13. The system of claim 12, wherein the feed rateof the second system is continuous, and the feed rate of the materialdeposition system is intermittent.
 14. The system of claim 10, whereinthe material deposition system comprises an extruder nozzle and a feeddrive that syncs with the syncing features when delivering the processedmaterial to the extruder nozzle, and the second system comprises ashaping system and a sizing system.
 15. The system of claim 14, whereinthe sizing system is configured to remove any extra material from theprocessed material and control a cross section area of the processedmaterial with a standard deviation of less than 1% of a target value.16. The system of claim 15, wherein the controller is configured tocreate lengths of the processed material with continuously variablecomposition ratios and with the syncing features placed in specificlocations along the processed material, the specific locations beingcoordinated with the composition ratios, and the cross section area ofthe processed material is constant.
 17. A method comprising:independently controlling a feed rate for each of at least two differentinput materials for three dimensional (3D) printing to generate aprocessed material that varies in composition along its length; and addsyncing features to the processed material, wherein the syncing featuresare useable by a 3D printer to synchronize the variation in compositionof the processed material during 3D printing of an object using theprocessed material.
 18. The method of claim 17, comprising creating datausable by the 3D printer to sync the processed material with volumetricor surface locations of the object during the 3D printing.
 19. Themethod of claim 18, wherein the 3D printer comprises a different fuseddeposition modeling (FDM) system, and creating the data comprisescreating the data in a data file usable by the different FDM system. 20.The method of claim 10, comprising: controlling the 3D printer to usethe processed material including the syncing features; and creatinglengths of the processed material with continuously variable compositionratios and with the syncing features placed in specific locations alongthe processed material, the specific locations being coordinated withthe composition ratios, and a cross section area of the processedmaterial is constant.